public static void Close(IVisio.Document doc, bool force_close)
        {
            if (force_close)
            {
                var new_alert_response = VA.Application.AlertResponseCode.No;
                var app = doc.Application;

                using (var alertresponse = new VA.Application.AlertResponseScope(app,new_alert_response))
                {
                    doc.Close();
                }
            }
            else
            {
                doc.Close();
            }
        }